fix: 测试 WS 客户端按字节流拆包并恢复群事件同步下发

internal/app/group/app.go

@@ -892,7 +892,6 @@ func (a *App) emit(ctx context.Context, recipients []string, groupID, event, end
 	if a.down == nil {
 		return
 	}
-	_ = ctx
 	frame := protocol.GroupEvent{
 		V: protocol.Version, Type: protocol.TypeGroupEvent,
 		GroupID: groupID, Event: event, EndpointID: endpointID, AtMs: atMs,
@@ -901,20 +900,14 @@ func (a *App) emit(ctx context.Context, recipients []string, groupID, event, end
 	if encErr != nil {
 		return
 	}
-	// 异步且略推迟：必须让处理该端上行的 worker 先 PublishDown resp。
-	// 若与 resp 同时向本连接注入 group_event，会与 mochi InlineClient 互相等待。
-	ids := append([]string(nil), recipients...)
-	go func() {
-		time.Sleep(20 * time.Millisecond)
-		seen := map[string]struct{}{}
-		for _, id := range ids {
-			if _, ok := seen[id]; ok {
-				continue
-			}
-			seen[id] = struct{}{}
-			_ = a.down.PublishDown(context.Background(), id, "", payload, port.PublishOpts{QoS: 0})
+	seen := map[string]struct{}{}
+	for _, id := range recipients {
+		if _, ok := seen[id]; ok {
+			continue
 		}
-	}()
+		seen[id] = struct{}{}
+		_ = a.down.PublishDown(ctx, id, "", payload, port.PublishOpts{QoS: 0})
+	}
 }
 
 func encodeFrame(v any) ([]byte, error) {